High quality thin diamond membranes that may have a thickness in the sub-micron range are of growing interest for a number of device applications, such as single photon sources, and quantum information processing devices.
A conventional process for fabricating such thin membranes includes chemical vapour deposition in connection with mechanical polishing and chemical etching. However, the quality of the thin diamond membranes fabricated by this process is often insufficient as such membranes usually have non-uniform thickness and relatively high surface roughness.
Other techniques, such as ion implantation and lift off, may be used to fabricate free-standing thin diamond membranes. However, these techniques introduce a residual built-in strain and damage resulting in membranes that are vulnerable to breakage and bowing which undermines subsequent processing of the membranes and degrades wave guiding properties and the quality of optical centres of the membranes.
There is need for improvement.